Karen's group designs and fabricates polymer nanocomposites containing carbon nanotubes and metal nanowires with the aim of understanding how to improve their mechanical, thermal, and especially electrical properties. More recently Karen has expanded her work to include simulations of electrical conductivity and polymer dynamics in the presence of nanoparticles. Karen pioneered the use of HAADF STEM to probe the nanoscale morphology in ion-containing polymers. Now, her group focuses on correlating the structures in these materials, including block copolymers, with transport properties.